LONDON: Copper prices rose on Thursday as available stockpiles in London Metal Exchange (LME) warehouses tumbled and a spike in the cost of metal for immediate delivery pointed to a tightening market. The dollar also slid to its weakest in nearly two years, making metals cheaper for buyers outside the United States.

Benchmark copper on the LME was up 0.8% at $6,534.50 a tonne at 1600 GMT, pushing towards last week's two-year high of $6,633. On-warrant copper inventories in LME-registered warehouses fell to 55,950 tonnes from about 250,000 tonnes in mid-May.

The premium for LME cash copper over three-month metal jumped to a 16-month high of $24.50 a tonne from a $30 discount in May. A premium signals tighter nearby supply. China's June aluminium imports surged by more than 490% year on year to an 11-year high of 288,783 tonnes as traders took advantage of lower prices abroad.

Citi raised its aluminium price forecasts to $1,900 a tonne in 2021 and $2,000 a tonne in 2022. LME aluminium was up 0.8% at $1,705 a tonne, zinc rose 1.1% to $2,237, nickel gained 4.1% to $13,670, lead added 1.2% to $1,826.50 and tin was up 1.5% at $17,850.